1. Field of the Invention
This invention relates to a wiper apparatus for wiping a window pane of the windshield, the rear window or so of vehicles with a wiper blade and, more particularly, to an improved apparatus suitable for wiping the window pane in a laterally elongated shape.
2. Description of the Prior Art
As the wiper apparatus for wiping the windshield, the apparatus is known, which is provided with a wiper motor, a pivot shaft, a wiper arm attached to the pivot shaft, a wiper blade connected to the wiper arm, and a wiper linkage connecting between the wiper motor and the pivot shaft, and structured so that the pivot shaft may be reciprocally turned according to rotation of the wiper motor through the wiper linkage, thereby oscillating the wiper arm on the windshield around the pivot shaft. Whereby the wiper blade connected to the wiper arm wipes the windshield by moving reciprocally in an arc in accordance with the oscillating movement of the wiper arm at the same time of being pressed against the windshield.
In the conventional wiper apparatus structured so that the wiper blade moves on the circular arc, when the apparatus is applied to wipe the windshield in a laterally elongated type, unwiped zones are left on both sides of the windshield. In order to prevent the occurrence of such the unwiped zone on the windshield, it has been tried to develop the wiper apparatus as disclosed in U.S. Pat. No. 4,642,838 or U.S. Pat. No. 3,651,699, which is possible to send the wiper blade so far as the both sides of the windshield by mechanically stretching the wiper blade by using the linkage at the time of wiping the both sides of the windshield. However, in the wiper apparatus of this kind, it is necessary to use the oversized specific linkage for extending the length of the wiper blade, accordingly there is a problem in that it is disadvantageous to apply such the wiper apparatus in view of configuration apace.
Furthermore, in the wiper apparatus provided with a planetary gear, a housing member contained with the planetary gear is formed in a lengthy oval shape, therefore the housing member of the planetary gear and the wiper arm overlap each other crosswise at the time of the operation. Accordingly, there is another problem in that there is the possibility that foreign substances may be caught between the housing member and the wiper arm.
It is, therefore, an object of this invention to provide a wiper apparatus, which is simple in the construction, but is possible to wipe the window pane without leaving unwiped zones even if it is applied to the window of the laterally elongated type, and possible to prevent foreign substances from being caught between wiper members.
The constitution of the wiper apparatus according to this invention for achieving the aforementioned object is characterized by comprising a wiper motor of a reversible type fixed on a body of said vehicle; a output shaft rotated reciprocally by the wiper motor in clockwise and anti-clockwise directions alternatively; a rotary housing fixed to the output shaft for rotating reciprocally together with the output shaft; a stationary gear disposed coaxially around about the output shaft and fixed on the vehicle body; an idler gear supported rotatably on the rotary housing and meshed with the stationary gear for reciprocally rotating on the rotary housing according to the reciprocating rotation of the rotary housing; an output gear supported rotatably on the rotary housing and driven rotationally by engaging with the idler gear; a pivot shaft supported rotatably on the rotary housing and fixed to the output gear; a wiper arm connected to the pivot shaft; and a wiper blade held by the wiper arm, wherein the rotary housing is formed in a circular shape, fixed coaxially to the output shaft and have a radius sufficient to house the stationary gear, the idler gear and the output gear.
In the wiper apparatus according to this invention, when the rotary housing contained with the stationary gear, the idler gear and the output gear is rotated reciprocally according to the reciprocal rotation of the output shaft by supplying an electric current to the wiper motor, the pivot shaft is rotated reciprocally against the reciprocally rotating rotary housing through the stationary gear, the idler gear and the output gear. Whereby, the wiper arm connected to the pivot shaft is oscillated above the windshield and the wiper blade held by the wiper arm wipes the window pane of the vehicle.
In this time, the wiper blade reaches a place more distant from the axis of the output shaft of the wiper apparatus because the substantial length of the wiper arm is elongated as much as a distance between the output shaft and the pivot shaft of the rotary housing. Therefore, the window pane of the laterally elongated type is wiped completely without leaving unwiped zones at the upper parts on the both sides thereof.
Furthermore, the rotary housing is formed in a circular shape with a radius sufficient to cover or house the aforementioned gears, accordingly foreign substances are never caught between the rotary housing and the wiper arm even in the case the rotary housing is rotated reciprocally.